This sounds interesting but I'm still not clear.
Q1 - does C514 mean the Punto-style box?
Q2 - is the Punto ELX90 unique in mating a Punto-style (C514?) box to a 128/Uno/ELX90 and later 1581 block? And wd that ELX90 box marry up to a Uno 1301 block?
Q3 - Your post above seems to say that all mk2 Unos except mk2 diesels and mk2(?) GTs had the Punto-type box, regardless of whether block type is 128/Uno type or FIRE. Really?